LESSON XIV 

 SUNLIGHT AND PLANT GROWTH 



Root hairs. After the seed has sprouted and the 

 roots have become attached to the soil, the new plant 

 must gather its own food materials and change them 

 into its own substance. Plants can take in only such 

 mineral matter as is dissolved in the soil water. Near 

 the ends of the small roots 

 are numerous hairlike cells 

 called root hairs. These 

 root hairs absorb the film 

 moisture held around the 



soil particles. This moisture, containing very small 

 amounts of the minerals of which the soil is composed, 

 becomes the sap which passes through the root and 

 stem to the leaves. 



Sunlight. - - Through the action of sunlight upon the 

 green leaves, the materials from the soil and air are built 

 into organic substances which finally become the 

 tissues of the plant. Water and carbon are combined 

 together in the leaves to form sugar. The carbon 

 comes from the carbon dioxide which the plants take 

 from the air. By other processes the sugar is combined 

 with nitrogen, phosphorus, potassium, sulphur, and 



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